The Header object represents a single HTTP header field. Both Request objects and Response objects have a Headers property, which returns a collection of their Header objects. Header fields are formatted as a single line of text containing a name-value pair separated by a colon. The Header.Name property gets or sets the name portion of the field, and the Header.Value property gets or sets the value portion.
Header fields transmit information about the message, such as the character encoding used, the size of the message, and the HTTP version supported. While some header fields can be used in both requests and responses, others are only appropriate in one context. For more information about specific HTTP header fields and example headers, see HTTP header fields reference.
While the properties of request Header objects are meant to be set, the server's response Header objects should be treated as read-only.